Final answer:
The principal force that prevents the aromatic bases in DNA and RNA from interacting with water is hydrophobic interactions, where the hydrophobic bases are sequestered inside the double helix away from water. option a is answer
Step-by-step explanation:
The principal force that keeps the bases in a polymer, such as DNA and RNA, from interacting with water is hydrophobic interactions.
Since the bases are hydrophobic, their placement on the interior of the double helix helps to stabilize the structure by avoiding contact with water. While hydrogen bonds are critical for the specificity of base pairing and holding the complementary strands of DNA together, they are not the principal force preventing interaction with water.
Similarly, van der Waals interactions also contribute to the overall stability of the DNA structure but are not the main force repelling water. Instead, it is the hydrophobic nature of the purine and pyrimidine bases that causes them to be sequestered away from the aqueous environment inside the helix, thus preventing interaction with water. option a is answer